/*
 * Copyright 2023 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package androidx.camera.viewfinder.view.internal.futures

import com.google.common.util.concurrent.ListenableFuture
import java.util.concurrent.ExecutionException
import java.util.concurrent.Future

/**
 * Cloned from concurrent-futures package in Guava to AndroidX namespace since we would need
 * ListenableFuture related implementation but not want to include whole Guava library.
 *
 * A callback for accepting the results of a [Future] computation asynchronously.
 *
 * To attach to a [ListenableFuture] use [Futures.addCallback].
 *
 * @param <V> </V>
 * @author Anthony Zana
 * @since 10.0
 */
interface FutureCallback<V> {
    /** Invoked with the result of the `Future` computation when it is successful. */
    fun onSuccess(result: V?)

    /**
     * Invoked when a `Future` computation fails or is canceled.
     *
     * If the future's [get][Future.get] method throws an [ExecutionException], then the cause is
     * passed to this method. Any other thrown object is passed unaltered.
     */
    fun onFailure(t: Throwable)
}
